This invention relates to shell eyelet headers, more particularly to shell eyelet axial lead headers, for planar contact semiconductive devices such as beam lead semiconductive devices and it is an object of the invention to provide an improved device of this nature.
After a solid state device, such as a transistor, a diode or an integrated circuit, has been completed, there remains the problem of connecting from the appropriate points on the solid state device to the external world. Most frequently this is done by forming wire bonds from the connecting points on the solid state device to some form of lead frame or other packaging article. Wire bonding is expensive and time consuming and much time and effort have been devoted to eliminating it. Particularly, it is desirable to enable the semiconductive or solid state devices to be connected to axial lead type headers such, for example, as the TO-18 and TO-5 type headers because of the great economy involved in utilizing these headers without the use of wire bonds.
Beam lead devices have been developed wherein the contacts are made to leads in the form of beams extending from the semiconductive device in order to eliminate wire bonds. In beam lead devices, all of the beams extend from the semiconductive device in a single plane. Similarly, other planar type contact mechanisms have been developed such, for example, as those in which small copper balls are bonded to the appropriate contact points on the planar surface of a semiconductive device. Thereafter, the semiconductor device or chip with copper balls bonded to all of the necessary contact points is turned upside down or flipped into position on some form of a lead frame or package arrangement. Prior art axial lead header devices for the foregoing purposes have not been satisfactory because of the additional effort necessary to bond the semiconductive device to the leads forming part of the headers or secondary operations have been necessary in order to make the ultimate device usable.
According to the invention, the bonding pad surface of the header may be made perfectly flat or planar and thus it is possible to bond or otherwise attach all of the contact points of a beam lead, or other planar contact, semiconductive device to the bonding pads of the header at the same time. Individual treatment for each contact and bonding pad are therefore eliminated.
Accordingly, it is a further object of the invention to provide an improved shell eyelet axial lead header for planar contact semiconductive devices which will eliminate the disadvantages of the prior art.
It is a further object of the invention to provide a shell eyelet axial lead header for semiconductive devices wherein multiple isolated bonding pads may be formed as part of axial lead packages of high reliability and moderate costs.